A new study in China suggests that it is possible to develop a safe vaccine against COVID-19, but the effectiveness of single shots remains unclear.

In the paper Lancet On Friday, Chinese researchers revealed that candidate vaccines have so far been tested in 108 healthy adults between the ages of 18 and 60 in Wuhan, China, where the pandemic began.

One-third of the participants received a low-dose candidate vaccine called Ad5-nCoV, one-third a moderate dose, and one-third a high-dose candidate vaccine. No participant reported a serious reaction to the vaccine, but some complained of injection site pain, fever, fatigue, headaches, and muscle aches.

Within two weeks of being vaccinated, the immune system of people who received all three doses showed some reaction, most of which developed a class of antibodies that could attach to the virus, but not necessarily destroy it. It does not mean. We have also developed a so-called neutralizing antibody that can kill the virus.

A major open question is whether this vaccine or other similar vaccines can produce sufficient neutralizing antibodies to protect people from the virus, according to the Baylor School of Medicine, National Tropical Medicine, Houston. Peter Jay Hotes said.

“Overall, the levels of neutralizing antibodies, a special type of antibody needed for protection, appear to be relatively low,” says Hotez.

However, no one knows the level of neutralizing antibodies needed to prevent infection with SARS-CoV-2, the virus that causes COVID-19.

Another option, according to Hotes, is to increase the effectiveness of this type of vaccine with a second type of vaccine.

Others have reiterated Hoteth’s cautious optimism.

It’s “exciting to see” the vaccine caused an immune response, said Bruce Walker, director of the Ragon Institute at MGH, MIT and Harvard University, who is studying the immune system and has recently been studying COVID- Moved the focus to 19. “But it’s unclear if these levels are necessary for protection, so investigators are reasonably cautious in their interpretation.”

There are several different types of vaccines that have been tested against the coronavirus that causes COVID-19. One of the tests is called an adenovirus vaccine because it uses a weakened cold virus to deliver genetic material to cells in the body. These cells then make the proteins found on the surface of the coronavirus, which stimulate the immune system to recognize and, hopefully, antibodies that destroy it.

One of the challenges with this Ad5-nCoV vaccine, according to Walker, is to use adenovirus 5 to deliver the payload. This is a cold virus that was previously exposed to approximately half of the population. In those people, the vaccine does not work well or at all because it clears the cold virus before the immune system becomes ill.

Older people are more likely to be exposed to the Ad5 cold virus. This is the least likely that the vaccine will work in people who need it most, simply because they live longer, Walker said in an email.

He pointed out that other adenovirus vaccines currently being developed to fight COVID-19 use various cold viruses, including Ad26 and the chimpanzee virus, to circumvent this problem.

About 100 teams worldwide are currently developing vaccines. Moderna Therapeutics, Cambridge, Massachusetts, and Oxford Vaccine Group also reporting initial results From people’s tests.

In a newly published study, researchers confirmed side effects both 1 and 4 weeks after vaccination. One patient in the highest dose group reported severe fatigue and arthralgia, but no complaints falling into the most serious category of complaints.

This early-stage study aims to ensure safety and to reconfirm safety and more closely examine efficacy, suggesting doses to be used for larger late-stage studies. is.

This research was funded by China’s National Key Research and Development Program, National Science and Technology University Project, and CanSino Biologics.

In a statement issued in this study, one scientist described the results as a “significant milestone,” but warned that more research was needed.

“The challenges in developing the COVD-19 vaccine are unprecedented, and the ability to elicit these immune responses does not necessarily indicate that the vaccine protects humans from COVID-19,” said Beijing Biotechnology Research. Said Wei Chen. I am in charge of research. “The results show a promising vision for the development of the COVID-19 vaccine, but there is still a long way to go before this vaccine becomes available to everyone.”

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